ABAP_DEMO篇33 SUM和COLLECT的用法

ABAP程序内表中的数量和金额字段  经常会需要合计， SUM和COLLECT 语法都能实现对数量和金额字段的合计。

1. SUM语法 
ABAP中SUM语句比不上EXCEL里的强大；
SUM只能在loop循环中使用，一般和AT-ENDAT配合使用。
使用SUM语句的先决条件包含在loop中使用加法INTO，以及指定的工作区域wa与内部表的行类型兼容。此外，当内部表itab的行类型包含表组件时，不能使用SUM。

DEMO

DATA:
  BEGIN OF wa,
    col1 TYPE i,
    col2 TYPE i,
  END OF wa,
  itab LIKE TABLE OF wa WITH EMPTY KEY.

itab = VALUE #( FOR i =  UNTIL i >
                FOR j =  UNTIL j > i
                ( col1 = i col2 = j ) ).

LOOP AT itab INTO wa.
  AT END OF col1.
    SUM.
    cl_demo_output=>write( wa ).
  ENDAT.
ENDLOOP.
cl_demo_output=>display( wa ).

内表ITAB中有15行数据

显示：

2. COLLECT语法

语法：COLLECT wa INTO itab [result].

此语句将工作区域的内容作为内部表itab中的单行插入，或者将其数值组件的值添加到具有相同主表键的现有行的对应值中。会对 数值型字段：I 类型， QUAN 类型，CURR类型的字段做汇总，字符型字段视为汇总条件，所以COLLECT 一般是用内表中的字符型字段作为KEY值 做汇总。

*&---------------------------------------------------------------------*
*& Report YCX_COLLECT1
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT ycx_collect1.

TYPES:
  BEGIN OF line,
    key TYPE c LENGTH ,
    num TYPE i,
  END OF line.
DATA
  itab TYPE SORTED TABLE OF line
            WITH UNIQUE KEY key.

DATA(rnd) = cl_abap_random_int=>create( seed = + sy-uzeit
                                        min  =
                                        max  =  ).

DO.
  COLLECT VALUE line( key = COND #( LET r = rnd->get_next( ) IN
                                    WHEN r =  THEN 'X'
                                    WHEN r =  THEN 'Y'
                                    WHEN r =  THEN 'Z' )
                      num =  ) INTO itab
          ASSIGNING FIELD-SYMBOL(<fs>).
  IF <fs>-num = .
    EXIT.
  ENDIF.
ENDDO.

cl_demo_output=>display( itab ).

再比如，通过工厂，物料汇总数量

DATA: BEGIN OF i_mi OCCURS ,
      matnr LIKE zhkmi-matnr,
      werks LIKE zhkmi-werks,
      menge LIKE zhkmi-menge,
      END OF i_mi.

START-OF-SELECTION.

    SELECT  matnr werks menge
    INTO CORRESPONDING FIELDS OF TABLE i_mi
    FROM zhkmi.

    SORT i_mi BY matnr werks.

    LOOP AT i_mi.
      i_collect-zkind = 'P'.
      i_collect-matnr = i_mi-matnr.
      i_collect-werks = i_mi-werks.
      i_collect-menge = i_mi-menge.
      COLLECT i_collect.
      CLEAR i_collect.
    ENDLOOP.

做个简单例子展示 sum和collect 实现汇总：

*&---------------------------------------------------------------------*
*& Report YCX_SUM
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT ycx_sum.

DATA: BEGIN OF line,
        col1 TYPE c,
        col2 TYPE i,
      END OF line.
DATA: itab       LIKE line OCCURS ,
      lt_collect LIKE line OCCURS  WITH HEADER LINE.

DO  TIMES.
  line-col1 = sy-index.
  line-col2 = sy-index ** .
  APPEND line TO itab.
ENDDO.

**显示内表数据
LOOP AT itab INTO line.
  WRITE: / line-col1, line-col2.
ENDLOOP.

WRITE:/'SUM汇总数据'.
**使用SUM 汇总
LOOP AT itab INTO line.
  AT END OF col1.
    SUM.
    WRITE: / line-col1, line-col2.
  ENDAT.
ENDLOOP.

WRITE:/'SUM汇(不使用AT END OF)'.
**使用SUM 汇总
LOOP AT itab INTO line.
  SUM.
  WRITE: / line-col1, line-col2.
ENDLOOP.

**使用COLLECT 汇总
LOOP AT itab INTO line.
  lt_collect-col1 = line-col1.
  lt_collect-col2 = line-col2.
  COLLECT lt_collect.
  CLEAR: lt_collect.
ENDLOOP.
WRITE:/'COLLECT汇总数据'.

LOOP AT lt_collect.
  WRITE: / lt_collect-col1, lt_collect-col2.
ENDLOOP.